LAUSR

Background: Gastric neuroendocrine tumors (G-NETs) are classified into well-differentiated NETs with three grades and poorly differentiated neuroendocrine carcinomas based on morphology and the Ki-67 index. Besides, G-NETs are broadly classified into four types based on clinical and pathophysiological features. Aim: To study clinical and pathological features of different types and grades of G-NET. Materials and Method: All G-NETs, diagnosed from January 2011 to December 2020, were included. Clinical presentation, peritumoral findings, lymph node status, and liver involvement were obtained and correlated with different grades and types of G-NETs. Results: NET was diagnosed in 88 cases. Tumors were graded as I, II, III, and carcinoma in 58, 14, 12, and 4 cases, respectively. Type I NET (49.2%) in the background of chronic atrophic gastritis was the most common type followed by type III (33.3%). Type I tumors were predominantly graded I (91.1%) and limited to the mucosa and submucosa. MEN-1-associated G-NET (type II) was seen in eight cases. All except one type II tumor was associated with ZES syndrome. Remarkably, peritumoral mucosa showed atrophy and intestinal metaplasia in 52.1% and 24.6% cases, respectively. Two cases were associated with adenocarcinoma. Lymph node metastasis was seen in all carcinoma and grade III cases. All carcinoma cases and 58.3% of grade III tumors showed liver metastasis. Conclusion: Biological behavior of G-NET varies with different types and grades of tumor. Typing and grading of G-NET should be done whenever possible to predict the aggressiveness of the tumor.